The present invention is directed to a method and apparatus for controlling requests for accessing resources in a wireless network. More specifically, the present invention is directed to a method and apparatus for making a remote unit more passive in its attempts to establish a connection to a base unit or base station in the wireless network.
It has long been known that there are many advantages to be derived from providing communication networks whereby communication terminals can communicate without the necessity of a wireline connection. One example of a wireless communication system is a mobile communications network in which mobile devices communicate via air links with base stations. The base stations are connected to mobile switching centers which control routing of communications into, typically, a wireline network.
Another wireless communication network configuration has been proposed. More specifically, it has been proposed to provide a service referred to as xe2x80x9cfixed wireless communicationxe2x80x9d. This configuration is meant to be either an adjunct to or substitute for local wireline communication to fixed locations. For example, as an alternative to local exchange carrier service via wireline local loops, it has been proposed to provide a fixed location with a wireless communication device referred to as a remote unit. The remote unit has transmission and receive capabilities for communicating with the base station via the available air links. It also can interface with a telephone or other communication device that is within or at the fixed location.
An example of this second system is illustrated in FIG. 1 of the present application. In this arrangement there are a plurality of remote units 101 to 104, each coupled to a communication device such as a telephone 105 to 108. The remote units communicate via air links to a base unit 110 that is coupled to a local wireline switch 111, for example, a No. 5 ESS supplied by Lucent Technologies.
In this fixed wireless communication system, it is desirable to approximate as closely as possible the service standards provided by wireline communications. As an example, in a wireline situation when a communication device such as a telephone goes off hook, there is a protocol for furnishing dial tone to the telephone device. The user of the communication device has a high expectation that dial tone will be supplied immediately upon taking the communication device off hook. It is desirable then in the fixed wireless context to provide comparable service to the end user. In this circumstance then, it is desirable that as soon as possible after the communication device goes off-hook the remote unit establish a connection to the base unit whereby dial tone can be provided to the telephone.
A problem may arise, however, where a plurality of remote units attempt to establish connections to the base unit at one time. In one example environment, there may be 2000 remote units assigned to a single base station. The base station cannot handle 2000 access requests at the same time. In fact, given the limitations on bandwidth for the airlinks between the remote unit and the base station, only ten or so calls can be handled at any given time. To reduce the burden on this shared bandwidth,the fixed wireless system can provide common access channels for call set up. These common access channels have a small amount of bandwidth for call setup and that small amount of bandwidth is shared by all of the remote units. It is possible in this configuration that various remote units will attempt to establish connections to the base unit at or about the same time thereby creating collisions in the shared bandwidth. This can put a heavy burden on the communication system and can reduce the likelihood that customers or end users will receive the type of service that they have come to expect from wireline communications. It would be beneficial if a technique was available for controlling requests for accessing resources in such a network.
The present invention provides a method and apparatus for controlling requests to access resources in a wireless network. A remote unit will first attempt to establish a connection with the base unit when a communication device associated with the remote unit goes off hook. If the base unit responds to this establishment attempt with an indication that the attempt has not been successful, then the remote unit waits a first predetermined amount of time before conducting a second establishment attempt. If this second establishment attempt is also unsuccessful, then the remote unit activates a timer for a second time interval longer than the first time interval. When the second time interval expires, another establishment attempt is made. If additional establishment attempts are unsuccessful, the time interval for further attempts can be expanded, thereby throttling back the remote unit""s establishment attempts. This reduces the load on the base unit and thereby reduces the likelihood of a complete system failure or freeze up in which the base unit could ultimately serve no one of the remote units because of the high likelihood of collision between the remote units. Thus, this invention provides that more of the remote units will receive service comparable to wireline service in terms of rapidly providing a dial tone when the communication device associated with the remote unit goes off hook.
In one embodiment of the invention, the timing intervals are set in accordance with a specification provided for wireline services, referred to as the TR303 specification. In accordance with those requirements, the first two time intervals are prescribed by the specification. Additional time intervals can be supplied and extended in accordance with a more detailed algorithm, such as one of the algorithms described in the detailed description set forth below.